PREDICTING HABS: POTENTIAL USE OF PHYTOPLANKTON SPECIES DIVERSITY AND DYNAMIC NATURE OF SUCCESSION EVENTS

Harmful algal blooms (HABs) are increasing worldwide. Our long-range goal must be to develop bloom-preventative management practices that are designed to sustain the quality and integrity of aquatic ecosystems. Such management efforts will require a monitoring scheme that provides early warning of HABs, i.e., before HAB-formation and possibly before HAB-initiation.
A potential monitoring scheme for this purpose may stem from the degree of phytoplankton succession dynamics and species diversity, where succession dynamics are quantified by summing the absolute value of the first derivative of the population curves for each phytoplankton species.
This scheme was tested using a detailed record of the phytoplankton community from Hartbeespoort Dam, South Africa. The record spanned a five-year period and contained recurrent blooms of cyanobacteria. Applying the scheme to this phytoplankton record revealed that during non-bloom periods, if both succession dynamics and species diversity were not high, a cyanobacteria bloom ensued. But if succession dynamics and species diversity were high a bloom did not occur.
The practicality of using this approach as an HAB early-warning tool with existing technology is discussed.